make database.toml for SIMPLE

make a database.toml file so that the new astrodb_utils function to load the database can be easily used.

https://astrodb-utils.readthedocs.io/en/stable/pages/api.html#module-astrodb_utils.loaders

[template database.toml](https://github.com/astrodbtoolkit/astrodb-template-db/blob/main/database.toml)